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<head>
<title>GFF Format Summary: Microsoft Windows Clipboard</title>
</head>
<body>
<h1><a name="SPEC-MICCLIP">Microsoft Windows Clipboard</a></h1>
<p>
<b>Also Known As:</b> CLP
<p>
<hr>
<p>

<p>
<table border=0>
<tr valign=top>
  <td align=left><b>Type</b></td>
  <td align=left>Metafile</td>
</tr>
<tr valign=top>
  <td align=left><b>Colors</b></td>
  <td align=left>Bilevel to 24-bit</td>
</tr>
<tr valign=top>
  <td align=left><b>Compression</b></td>
  <td align=left>None</td>
</tr>
<tr valign=top>
  <td align=left><b>Maximum Image Size</b></td>
  <td align=left>32Kx32K and 2Gx2G pixels</td>
</tr>
<tr valign=top>
  <td align=left><b>Multiple Images Per File</b></td>
  <td align=left>Yes</td>
</tr>
<tr valign=top>
  <td align=left><b>Numerical Format</b></td>
  <td align=left>Little-endian</td>
</tr>
<tr valign=top>
  <td align=left><b>Originator</b></td>
  <td align=left>Microsoft Corporation</td>
</tr>
<tr valign=top>
  <td align=left><b>Platform</b></td>
  <td align=left>Microsoft Windows</td>
</tr>
<tr valign=top>
  <td align=left><b>Supporting Applications</b></td>
  <td align=left>Microsoft Clipboard and ClipBook Viewer</td>
</tr>
<tr valign=top>
  <td align=left><b>See Also</b></td>
  <td align=left><a href="gffse:/format.micbmp">Microsoft Bitmap</a>,
   <a href="gffse:/format.micmeta">Microsoft Metafile</a>, DIF,
   <a href="gffse:/format.micsylk">SYLK</a>, RTF</td>
</tr>
</table>
<p>
<b>Usage</b><br>
Used as a "one-format-saves-all" solution for easily storing data
in Windows to disk.
<p>
<b>Comments</b><br>
A useful and under-utilized format. Programmers can safely assume 
that every installation of Windows will have the ability to read and write
Clipboard files. 
<p>
<hr>
<p>
<A NAME="MICCLIP-DMYID.1"><!-- Overview anchor --></A>
<p>
The Clipboard file format is used to store Microsoft Windows
Clipboard data to disk. The Clipboard is an area of shared memory found
in the Windows operating system, and is the simplest mechanism
available to exchange data between applications running in the
Windows environment.
<p>
<B>Contents:</B><br>
<A HREF="#MICCLIP-DMYID.2">File Organization</a><br>
<a href="#MICCLIP-DMYID.3">File Details</A><br>
<A HREF="#MICCLIP-DMYID.4">For Further Information</A><br>
<p>
A set of functions in the Windows API is used to transfer data between
the Clipboard and Windows applications. For example, the Cut, Copy,
Clear, Paste, and Undo functions found in many Windows applications
all use these function to access Clipboard memory as an area for
temporary storage and data exchange. However, only one Windows
application may access the Clipboard at a time. The Clipboard can also
be accessed directly using the built-in Windows applications Clipboard
Viewer and ClipBook Viewer.
<p>
The Clipboard Viewer is a simple application used to view the entire
contents of the Clipboard and to save its data to disk using the CLP
file format. The ClipBook Viewer is an extended version of the
Clipboard Viewer that allows stored data to be divided into separate
pages of information and shared over a Microsoft (NetBEUI) network
using the OLE or DDE protocols. Each page in the ClipBook may hold the
data captured by a single Cut or Copy operation. ClipBook may contain
a maximum of 127 separate pages, each identified by a name up to 47
characters in length, and limited in size only by the amount of
available disk space. Each page of the ClipBook may be stored in a
separate CLP file.
<p>
The Clipboard Viewer and ClipBook Viewer are separate programs, but
both use the executable file name <i>clipbrd.exe</i>, so it is not likely
you will find both programs installed in the same Windows
environment.
<p>
The Clipboard Viewer under Windows 2.<i>x</i> and 3.<i>x</i>
is found in the Main group box. Windows for Workgroups
3.<i>x</i> and Windows NT 3.<i>x</i> provide only
the ClipBook Viewer, also found in the Main group box. 
<p>
Clipboard Viewer is not installed by default in Windows 95. To
install the Clipboard Viewer under Windows 95, you must select
Add/Remove Programs in Control Panel, click the Windows Setup tab,
click Accessories, and then click Details. Click the Clipboard Viewer
check box to select it, and then click OK or Apply. The Clipboard
Viewer will be installed and a shortcut will be placed in the
Accessories menu under the Programs menu.
<p>
The CD-ROM version of Windows 95 and CD-ROM Extras for Microsoft
Windows 95 Upgrade also includes the ClipBook Viewer, but the floppy
disk version of Windows 95 does not. If you install Windows 95 over
Windows for Workgroups version 3.1, and during Setup choose to not
install the Windows 95 Clipboard Viewer, Windows 95 retains and will
use the Windows for Workgroups ClipBook Viewer.
<p>
It is important to realize that both the Clipboard and ClipBook
Viewer are only applications that access the Clipboard and its data,
and are not the Clipboard themselves. This point is often a source of
confusion for both Windows users and programmers alike.
<p>

<h2><A NAME="MICCLIP-DMYID.2">File Organization</A></h2>
<p>
Clipboard files use a very simple data format, but can be quite
complicated because they can store many types of data. The CLP file
format begins with a header and is followed by a directory of one or
more records that indicates the type and location of data within the
Clipboard file. Following these records are the actual Clipboard data.
(See Figure Microsoft Windows Clipboard-1.)
<h4>Figure Microsoft Windows Clipboard-1: Basic layout of a CLP file</h4>
<p>
<img src="./msclip01.gif" alt="[Graphic: Figure Microsoft Windows Clipboard-1]">
<p>
There will be one section of data per record.
The standard Clipboard data formats are listed in Table Microsoft
Windows Clipboard-1.
<p>
<table>
<caption>Table Microsoft Windows Clipboard-1: Standard Clipboard Data Formats</caption>
<tr>
  <th align=left>Data Format</th>
  <th align=left>Format ID</th>
  <th align=left>Description</th>
</tr>
<tr>
  <td align=left>TEXT</td>
  <td align=left>0x0001</td>
  <td align=left>ANSI text</td>
</tr>
<tr>
  <td align=left>BITMAP</td>
  <td align=left>0x0002</td>
  <td align=left>Windows Device-Dependent Bitmap</td>
</tr>
<tr>
  <td align=left>METAFILE</td>
  <td align=left>0x0003</td>
  <td align=left>Windows Clipboard Metafile</td>
</tr>
<tr>
  <td align=left>SYLK</td>
  <td align=left>0x0004</td>
  <td align=left>Microsoft spreadsheet format</td>
</tr>
<tr>
  <td align=left>DIF</td>
  <td align=left>0x0005</td>
  <td align=left>Soft Arts spreadsheet format</td>
</tr>
<tr>
  <td align=left>TIFF</td>
  <td align=left>0x0006</td>
  <td align=left>Adobe Tag Image File Format</td>
</tr>
<tr>
  <td align=left>OEMTEXT</td>
  <td align=left>0x0007</td>
  <td align=left>ASCII text</td>
</tr>
<tr>
  <td align=left>DIB</td>
  <td align=left>0x0008</td>
  <td align=left>Windows Device-Independent Bitmap</td>
</tr>
<tr>
  <td align=left>PALETTE</td>
  <td align=left>0x0009</td>
  <td align=left>Windows DIB Color Palette</td>
</tr>
<tr>
  <td align=left>PENDATA</td>
  <td align=left>0x000A</td>
  <td align=left>Microsoft Pen Windows data</td>
</tr>
<tr>
  <td align=left>RIFF</td>
  <td align=left>0x000B</td>
  <td align=left>Microsoft Resource Interchange File Format</td>
</tr>
<tr>
  <td align=left>WAVE</td>
  <td align=left>0x000C</td>
  <td align=left>Microsoft Audio File Format</td>
</tr>
<tr>
  <td align=left>UNICODETEXT</td>
  <td align=left>0x000D</td>
  <td align=left>Unicode text (Windows NT only)</td>
</tr>
<tr>
  <td align=left>ENHMETAFILE</td>
  <td align=left>0x000E</td>
  <td align=left>Windows Enhanced Metafile (Windows 95 and NT only)</td>
</tr>
<tr>
  <td align=left>HDROP</td>
  <td align=left>0x000F</td>
  <td align=left>Double NULL-terminated list of strings (Windows 95 only)</td>
</tr>
<tr>
  <td align=left>LOCALE</td>
  <td align=left>0x0010</td>
  <td align=left>Language and character set specifier (Windows 95 only)</td>
</tr>
</table>
<p>
Most of the native Windows data formats are supported by the
Clipboard. The Clipboard is also capable of storing private or
user-defined data formats (Table Microsoft Windows
Metafile-2). Applications such as the
Microsoft Windows Write word processor store a variety of private
data formats using the Clipboard. You can also store any other file
format as private data inside of a CLP file and read the file into
the Clipboard using the Clipboard Viewer or your own Clipboard-aware
application. Your application is then responsible for parsing and
displaying the private data.
<p>
<table>
<caption>Table Microsoft Windows Clipboard-2: Private Clipboard Data Formats</caption>
<tr>
  <th align=left>Data Formats</th>
  <th align=left>Format ID</th>
  <th align=left>Description</th>
</tr>
<tr>
  <td align=left>OWNERDISPLAY</td>
  <td align=left>0x0080</td>
  <td align=left>Private data not displayable on the Clipboard</td>
</tr>
<tr>
  <td align=left>DSPTEXT</td>
  <td align=left>0x0081</td>
  <td align=left>Display Text</td>
</tr>
<tr>
  <td align=left>DSPBITMAP</td>
  <td align=left>0x0082</td>
  <td align=left>Display Bitmap</td>
</tr>
<tr>
  <td align=left>DSPMETAFILEPICT</td>
  <td align=left>0x0083</td>
  <td align=left>Display Metafile Picture</td>
</tr>
<tr>
  <td align=left>DSPENHMETAFILE</td>
  <td align=left>0x008E</td>
  <td align=left>Display Enhanced Metafile</td>
</tr>
<tr>
  <td align=left>PRIVATEFIRST</td>
  <td align=left>0x0200</td>
  <td align=left>First Private Data Format</td>
</tr>
<tr>
  <td align=left>PRIVATELAST</td>
  <td align=left>0x02FF</td>
  <td align=left>Last Private Data Format</td>
</tr>
<tr>
  <td align=left>GDIOBJFIRST</td>
  <td align=left>0x0300</td>
  <td align=left>First Private Graphics Device Interface Object</td>
</tr>
<tr>
  <td align=left>GDIOBJLAST</td>
  <td align=left>0x03FF</td>
  <td align=left>Last Private Graphics Device Interface Object</td>
</tr>
</table>
<p>
When a CLP file is read by a Clipboard viewer, the data of the first
usable entry will be displayed. It is therefore necessary to store
the most important data first in a CLP file. For example, you might
store the same piece of text in both the TEXT and OEMTEXT formats.
Windows would use the TEXT data, and other applications that use only
the ASCII character set would use the OEMTEXT data. The same text
data could also be stored as RTF and UNICODETEXT in the same CLP
file.
<p>
Not every flavor of Windows is capable of supporting every Clipboard
data format. For example, ENHMETAFILE is not supported by Windows 3.<i>x</i>
and UNICODETEXT is presently only supported by Windows NT. If Windows
cannot find data in a usable format on the Clipboard, it will attempt
to convert a recognized data format to one considered more suitable.
For example, TEXT or OEMTEXT data may be converted to UNICODETEXT;
METAFILEPICT to ENHMETAFILE; BITMAP to DIB, and DIB to PALETTE.
Unrecognized formats are ignored and not displayed by the viewers.
<p>
<h2><A NAME="MICCLIP-DMYID.3">File Details</A></h2>
<p>
The CLP header is four bytes in length and has the following format:
<pre>
typedef struct _ClpHeader
{
    WORD FileId;        /* File identifier (always 3C50h) */
    WORD FormatCount;   /* Number of records in directory */
} CLPHEADER;
</pre>
<p>
FileId is used to identify a CLP file. This value is always 3C50h.
<p>
FormatCount is the number of record entries in the format directory.
<p>
<h3><A NAME="MICCLIP-DMYID.3.1">Clipboard Records</A></h3>
<p>
Following the header is one or more records that indicate the type
and location of data within the Clipboard file. The number of records
is specified by the FormatCount field in the header. Each record may
be from 11 to 89 bytes in length and has the following format:
<pre>
typedef struct _FormatRecord
{
    WORD  FormatId;       /* Format Identifier */
    DWORD DataLength;     /* Number of bytes in the data */
    DWORD DataOffset;     /* Offset of the data in the file */
    BYTE  FormatName[];   /* Format name */
} FORMATRECORD;
</pre>
<p>
FormatId identifies the type of data indicated by this record. Valid
values for this field are listed in the Format ID columns of Tables
Microsoft Windows Clipboard-1 and Microsoft Windows Clipboard-2.
<p>
DataLength specifies the length of the data in bytes.
<p>
DataOffset indicates the offset of the data within the Clipboard file.
The offset is always calculated from the beginning of the file.
<p>
FormatName is a plain-text string that describes the name of the
format. This string will be "Text" for TEXT data, "Bitmap" for BITMAP
data, and so forth. Private data types, such as "Rich Text Format",
will also be described. This string may be up to 78 characters in
length and is always terminated with a NULL (0x00).
<p>
The format of an entire Clipboard file can be defined as such:
<pre>
typedef struct _ClipboardFormat
{
    CLPHEADER ClpHeader;
    FORMATRECORD ClpRecords[ClpHeader.FormatCount];
    BYTE Data[];
} CLIPBOARDFORMAT;
</pre>
<p>

<h3><A NAME="MICCLIP-DMYID.3.2">Clipboard Data</A></h3>
<p>
The CLP format supports a bewildering variety of data formats. Most of
these formats are documented as separate file formats described
elsewhere in this book. Following is a description of the format data
types listed in Tables Microsoft Windows Clipboard-1 and Microsoft
Windows Clipboard-2.
<p>
TEXT is one or more strings of 8-bit ANSI characters. Each string is
terminated by a carriage return (0x0D) and a line feed (0x0A). A NULL
(0x00) byte indicates the end of the TEXT data. The ANSI character set
is the default character set used by Windows.
<p>
BITMAP is a Microsoft Device-Dependent Bitmap (DDB). Refer to the
<a href="gffse:/format.micbmp">Microsoft Windows Bitmap</a>
format article for more information on the DDB format.
<p>
METAFILE is a standard Windows Metafile, but is preceded by an
additional header used by the Clipboard. Refer to the
<a href="gffse:/format.micmeta">Microsoft Windows Metafile</a>
format article for the format of the Clipboard
Metafile.
<p>
SYLK is the Microsoft Symbolic Link data format used by Microsoft
Excel, Chart, and Multiplan to store spreadsheet data. The SYLK data
is stored as ASCII text with each line terminated with a carriage
return and line feed. Refer to the
<a href="gffse:/format.micsylk">Microsoft SYLK</a>
file format article for more information on the SYLK format.
<p>
DIF is the Software Arts Data Interchange Format used to store
spreadsheet data. The DIF data is stored as ASCII text with each line
terminated with a carriage return and line feed. Refer to the
<a href="gffse:/format.lotusdif">Lotus DIF</a> file format article
for more information on the DIF format. 
<p>
TIFF is the Tag Image File Format created by Aldus, Hewlett-Packard,
and others, and is now administered by Adobe Systems. Refer to the
<a href="gffse:/format.tiff">Tag Image File Format</a> article
for further information on TIFF.
<p>
OEMTEXT is one or more strings of 7-bit ASCII characters. Each string
is terminated by a carriage return (0x0D) and a line feed (0x0A). A
NULL (0x00) byte indicates the end of the OEMTEXT data. The ASCII
character set is the default character set used by MS-DOS.
<p>
DIB is a Microsoft Device-Independent Bitmap (DIB). Refer to the
<a href="gffse:/format.micbmp">Microsoft Windows Bitmap</a> format
article for more information on the DIB format.
<p>
PALETTE is a DIB color palette. Refer to the
<a href="gffse:/format.micbmp">Microsoft Windows Bitmap</a>
format article for more information on the DIB color palettes.
<p>
RIFF is the Microsoft Resource Interchange File Format. This is
Microsoft's "store anything" multimedia file format. Refer to the
<a href="gffse:/format.micriff">Microsoft RIFF</a> article
for more information.
<p>
WAVE is the Microsoft Waveform audio file format (.wav files). A wave
file is nothing more than a RIFF file that stores only digital audio
data.
<p>
UNICODETEXT is one or more strings of 16-bit Unicode characters. Each
string is terminated by a carriage return (0x000D) and a line feed
(0x000A). A NULL (0x0000) byte indicates the end of the UNICODETEXT
data. The Unicode character set is the default character set used by
Windows NT and Win32.
<p>
ENHMETAFILE is an Enhanced Windows Metafile found on Win32 systems.
Refer to the <a href="gffse:/format.micmeta">Microsoft Windows
Metafile</a> format article for the format
of the Enhanced Metafile.
<p>
OWNERDISPLAY is private data that is not recognized by the Clipboard,
and is therefore not displayed by the Clipboard Viewer. The
FormatName field of this data's record should yield a clue as to the
format of the data.
<p>
DSPTEXT is a collection of private text. This data is stored using the
same format as the TEXT format, and will be displayed as text, but is
not available via the TEXT format ID.
<p>
DSPBITMAP is a collection of private text. This data is stored using
the same format as the BITMAP format, and will be displayed as text,
but is not retrievable using the BITMAP format ID.
<p>
DSPMETAFILEPICT is a collection of private text. This data is stored
using the same format as the METAFILEPICT format, and will be
displayed as text, but is not retrievable using the METAFILEPICT
format ID.
<p>
DSPENHMETAFILE is a collection of private text. This data is stored
using the same format as the ENHMETAFILE format, and will be
displayed as text, but is not retrievable using the ENHMETAFILE
format ID.
<p>
GDIOBJFIRST and GDIOBJLAST are a range of reserved values use to
register private GDI objects. GDI objects include brushes, pens,
palettes, and fonts. Under Windows the object is created first in
memory and then saved to the Clipboard using the SetClipboardData()
functions call. The handle of the GDI object and a value in the
range of GDIOBJFIRST and GDIOBJLAST (inclusive) are passed to the
function.
<p>
PRIVATEFIRST and PRIVATELAST are a range of reserved values used to
register private data formats. There is no official registration of 
private data format numbers, so your reader application needs to both
recognize this value and the FormatName string to properly identify
the private data.
<p>
For example, let's say you want to import a 32K IFF file into your
application through the Clipboard. You might construct a CLP file
with a single record and containing the IFF file data:
<pre>
typedef struct _PrivateIffFormat
{
    WORD  FileId;           /* 0x3C50 */
    WORD  FormatCount;      /* 0x0001 */
    WORD  FormatId;         /* 0x0200 */
    DWORD DataLength;       /* 0x00007FFF */
    DWORD DataOffset;       /* 0x00000026 */
    BYTE  FormatName[];     /* "Interchange File Format\0" */
    BYTE  Data[];           /* The entire IFF file */
} PRIVATEIFFFORMAT;
</pre>
<p>
In this example we see a CLP file that contains a single record
describing a private format with an ID value of 0x200. The data is 32K
in size and begins 39 bytes into the file. Once this file has been
read into the Clipboard the IFF file data may be read and parsed by
any application that can access the Clipboard.
<p>

<h2><A NAME="MICCLIP-DMYID.4">For Further Information</A></h2>
<p>
There is no official CLP file format specification. The Clipboard
File Format and Clipboard management functions are described in
detail in:
<blockquote>
<p><i>Microsoft Windows Programmer's Reference</i>, Volumes 2 and 4, Microsoft Press, Redmond, WA, 1990.
</blockquote>
<p>
The Microsoft Developers Network (MSDN) distributes several files
containing information on the CLP format. These files may be found on
the MSDN CD, or on the Microsoft Web site at:
<blockquote>
<i>http://www.microsoft.com/developr/MSDN/</i>
</blockquote>
<p>

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